Effect of human-driven hydrological change on vegetation distribution in the Shiyang River Basin

China has implemented large-scale hydraulic engineering projects in arid regions where water resources are severely scarce to efficiently maximize limited water resources for production and domestic needs. The processes and consequences of how the change of hydrological factors affects vegetation distribution remain unclear. This study employed multi-source remote sensing data to investigate the impact of hydrological factors on vegetation distribution in the Shiyang River Basin (SRB) in the arid region in Northwestern China. The results indicate that: (1) The NDVI values in the SRB showed a fluctuating upward trend of (0.0014/yr), with vegetation increase occurring in 62.71% of the area while vegetation degradation was observed in only 6.44% of the area. (2) The Surface Water Storage Anomaly (SWSA) shows an increasing trend of (0.112 mm/month), while Terrestrial Water Storage Anomaly (TWSA) and Groundwater Storage Anomaly (GWSA) exhibit significant declines at rates of -0.124 mm/month and -0.236 mm/month, respectively. (3) Vegetation growth on agricultural land and in planted forests has shown significant growth, in contrast to the general degradation of natural vegetation that is dependent on groundwater. In addition, surface water inputs directly catalyze vegetation growth dynamics. However, the complex mechanisms linking vegetation increase and decreasing terrestrial water reserves in arid regions still need to be studied in depth. The potential negative ecological impacts that may result from the continuous decline of terrestrial and groundwater reserves should not be taken lightly.